Grounded female socket and plug

ABSTRACT

A female socket having a plug-receiving or similar bodyreceiving opening which terminates in a plug-accommodating seat, and wherein the necessary positive and negative electrical contacts of the same are located about the socket opening while a ground electrical contact is advantageously located in the plugaccommodating seat. Accordingly, threaded engagement of the plug, lightbulb, or the like within the socket automatically results in operation of the same with the attendant safety factor of a connection to ground.

waited States Patent Krause Feb. 22, 1972 [54] GROUNDED FEMALE SOCKETAND PLUG [72] Inventor: Edward F. Krause, 105 Birs Ave., Lindenhurst,NY. 11757 [22] Filed: Aug. 3, 1970 [21] Appl. No.: 60,673

[521 u.s.c|. ..339/14R,339/176L,339/183 [51] lnt.Cl ..H0lr3/06 5sFieldofSearch ..339/l4,59,182,183,176L,

[56] References Cited UNITED STATES PATENTS 2,170,131 8/1939 Doremus..339/59 3,060,41710/1962 Blake 2,004,105 6/1935 Farish..... 2,118,8575/1938 Morford 2,708,714 5/ 1955 Stevens ..240/54 Primary ExaminerMarvinA. Champion Assistant Examiner-Robert A. Hafer Attorney-Bauer & Amer[57] ABSTRACT A female socket having a plug-receiving or similarbodyreceiving opening which terminates in a plug-accommodating seat, andwherein the necessary positive and negative electrical contacts of thesame are located about the socket opening while a ground electricalcontact is advantageously located in the plug-accommodating seat.Accordingly, threaded engagement of the plug, lightbulb, or the likewithin the socket automatically results in operation of the same withthe attendant safety factor of a connection to ground.

1 Claims, 4 Drawing Figures PATENTED FEB 2 2 I872 FIG! INVENTOR. EDWARDF. KRAUSE ATTORNEY GROUNDED FEMALE SOCKET AND PLUG The present inventionrelates generally to an improved combination female socket and plug, andmore particularly to a female socket and plug construction whichprovides grounded operation for any electrical device electricallyconnected to the same.

While there are known prior art electrical devices which function bothas a socket per se and also with an added female plug, none of theseprior art devices, except those with unduly complicated constructions,provide the noteworthy safety factor of being grounded during electricalcurrent transmission. The additional ground electrical contact and therequirement of establishing a grounding connection therewith invariablycomplicates the construction and mode of functioning of the combinedsocket and plug.

Broadly, it is an object of the present invention to provide a groundedcombination socket and plug overcoming the foregoing and othershortcomings of the prior art. Specifically, it is an object to providea threadably engageable cooperating socket and plug which has a groundconnection during electrical current transmission that is establishedmerely upon the threading of the plug within the socket.

The combined socket and plug electrical device demonstrating objects andadvantages of the present invention includes in the areas of the socketand plug that make contact during threaded engagement of the plug withinthe socket a cooperating pair of ground electrical contacts in thepreferred form of rings. Thus, the ground connection therebetween isestablished when the rings contact each other and is not criticallyaffected by the tightness of the threaded engagement.

The above brief description, as well as further objects, features andadvantages of the present invention, will be more fully appreciated byreference to the following detailed description of a presentlypreferred, but nonetheless illustrative embodiment in accordance withthe present invention, when taken in conjunction with the accompanyingdrawings, wherein:

FIG. I is a perspective view illustrating a typical use of the groundedfemale socket and plug hereof;

FIG. 2 is a side elevational view, in section and on an enlarged scale,illustrating internal structural features of the grounded female socketportion of the invention;

FIG. 3 is similarly a sectioned side elevational view, but illustratinginternal structural features of the plug which is adapted to bethreadably received in the socket; and

FIG. 4 is a front plan view of the plug.

Reference is now made to the drawings, and particularly FIG. 1,illustrating a typical use of the combination socket and plug hereof,generally designated 10, to provide an electrical connection for plurallights to a three-wire romex cable 12. Specifically, the device isillustrated in FIG. 1 in its contemplated form as a female socket 22 inwhich it threadably receives a lightbulb 14. Also illustrated in FIG. 1is a modification of the device 10 wherein it includes in lieu of thebulb 14 a female plug 16 which is adapted to accommodate a male plugcounterpart 18 of an electrical conductor 20.

As will be described in greater detail subsequently, a

noteworthy feature of the device 10, whether in the form of a femalesocket 22 or whether modified with the addition of the plug 16, is thatin both forms the device 10 is grounded or, in other words, has aconnection to ground which minimizes the possibility of a short circuit,electrical shock or similar mishap during use of the device 10. Whilethere are known prior art electrical devices which function both as asocket per se and also with an added female plug, none of these priorart devices have the safety factor of being grounded during operationand yet have the simplified construction and other noteworthy featureswhich characterize the device 10 hereof.

Referring to FIG. 2, the socket part of the device 10, more specificallydesignated 22, includes a plastic body 24 appropriately formed with asocket opening 26 for accommodating the base of the previously notedlightbulb 14 or the like, or the previously noted plug 16. The socket 26terminates with an end counterbore 28 which provides a pair oftransversely oriented walls 30 and 32 which cooperate to define a seatfor a peripheral projection of the plug 16, all as will be described ingreater detail subsequently. At this point in the description, however,it is convenient to note that the base or inner end of the socketopening 26 is advantageously molded with threads which, in turn, readilypermit the accommodation of a metal shell 34 having correspondingthreads formed therein. The metal threads 34 serve as one electricalcontact for the device 10 and is appropriately connected to a conductor36 which, in practice, is affective in establishing an electricalconnection to one of the three wires of the cable 12. The second metalcontact 38, located at the extreme base of the socket opening 28, servesas the other electrical contact of the female socket 22. Contact 38 alsois electrically connected to a conductor 40 through which electricalcontact is established with another wire of the three-wire cable 12.

The ground connection for the device 10 which, according to the presentinvention, is embodied in the femalesocket 22, is in the form of acircular ring 42 which is appropriately force-fit in place within theend counterbore 28. Despite this exposed position of the ground contact42, there is no added danger to the user because there is no currentflow therethrough as there is in the case of the positive and negativeelectrical contacts 34 and 38. The ground electrical contact 42, likethe other electrical contacts 34 and 38, is electrically connected to aconductor 44 through which an electrical connection is establishedbetween the ground 42 and the ground wire of the three-wire cable 12. Asa consequence of the just-described construction of the female socket22, a conventional threaded base of a lightbulb 14 in its threadablyengaged condition within the socket 34 is effective in establishing thenecessary positive and negative electrical connections with the contacts34 and 38 to cause operation of the lightbulb 14. Additionally, physicalcontact' is made with the ground electrical contact 42 to causegrounding of the electric bulb 14 during its operation and therebyproviding the attendant safety factor which results from such groundedoperation.

In accordance with the present invention, it is further contemplatedthat the female socket 22 will threadably accommodate the female plug 16which, in turn, will accommodate the previously noted three-pronged maleplug 18. To this end, plug 16 includes a large diameter base 46 having asmaller diameter forwardly projecting segment 48. At the front end ofthe segment 48 are cooperating positive and negative electrical contacts50 and 52 respectively connected via conductors 54 and 56 to maleprong-receiving openings 58 and 60 in the plug base 46.

Additionally, and as clearly illustrated in FIG. 3, at the juncture ofthe segment and base, there is a peripheral projection 62 which is of anappropriate radial extent to seat snugly in the seat 28, or-moreparticularly in the shoulder formed by the transverse walls 30 and 32.Advantageously provided on a radial wall of the projection 62 is anelectrical ground contact 64, in the preferred form of a ring, whichcooperates with the previously noted ring 62 in establishing acontinuation for the plug 16 of the ground electrical connection of thesocket 22. This electrical connection is completed by a conductor 66which is electrically connected from the ground contact 64 to a shapedmale plug prong-receiving opening 68 which is provided in the plug base46.

From the foregoing, it should be readily appreciated that there has beendescribed herein a combination grounded female socket and plug 10 whichprovides a grounded electrical connection whether used merely as asocket or with the plug addition. Moreover, when the plug 16 is providedwith its seated position within the socket 22, this automaticallyresults in physical contact of the cooperating ground electricalcontacts 42 and 64 and thereby provides the necessary electricalconnection for grounded operation of any electrical device which isplugged into the plug 16.

A latitude of modification, change and substitution is intended in theforegoing disclosure and in some instances some having a groundelectrical contact disposed therein.

and a plug formed with a large diameter base and a threaded smallerdiameter body adapted to threadably engage with said female screwsocket,

said plug having positive and negative electrical contacts arranged onsaid body and a circular grounded electrical contact arranged thereon atthe change in diameter existing at the juncture of said base with saidbody,

whereby threaded engagement of said plug with said female screw socketestablishes the electrical connections of said positive, negative andground electrical contacts.

1. A combination grounded female socket and plug comprising a sockethousing having an open-ended socket compartment, a female screw socketdisposed in said socket compartment having positive and negativeelectrical contacts, a counterbore in said open end of said socketcompartment having a ground electrical contact disposed therein, and aplug formed with a large diameter base and a threaded smaller diameterbody adapted to threadably engage with said female screw socket, saidplug having positive and negative electrical contacts arranged on saidbody and a circular grounded electrical contact arranged thereon at thechange in diameter existing at the juncture of said base with said body,whereby threaded engagement of said plug with said female screw socketestablishes the electrical connections of said positive, negative andground electrical contacts.